Perhaps George Bailey is to blame. The lead character in Frank Capra's "It's Wonderful Life" stares at that bridge on Christmas Eve, thinking about committing suicide and perhaps sparking the conventional wisdom that the suicide rate rises around Christmastime.

That's been the thinking in the 60-plus years since that movie was released, giving rise to a myth that is almost as storied as Santa Claus, one researcher says.

"It is totally a myth," says Dan Romer, research director of the Adolescent Communication Institute of the Annenberg Public Policy Center at the University of Pennsylvania. "December is actually a low point for suicides."

Mr. Romer has been tracking media reports of the December suicide myth in America for more than 10 years. He started at the turn of the millennium, when there was an uptick in the number of people who thought the world would end when the calendar hit 2000.

At that time, he found just 23 percent of news reports debunked the suicide myth. By 2006, 91 percent of stories were mentioning that the believed increase was not true. By last holiday season, however, Mr. Romer found that the number of reports debunking the myth was down to 62 percent, meaning more than one-third of stories were still reporting that suicides increase over the holidays.

The peak time for suicides is May, says Paula Clayton, a psychiatrist and medical director of the American Foundation for Suicide Prevention. The U.S. Centers for Disease Control and Prevention reports that 33,000 Americans commit suicide each year.